Envelope for transparency

Abstract

An improved envelope for transparencies for overhead projectors comprising a substantially rectangular pocket made of a transparent sheet material, the pocket having two longitudinal side edges connected by shorter side edges, and being open at least along one side edge for insertion of a transparency, at least one opaque flap attached in a foldable manner along one of the side edges by means of a flexible adhesive tape, the tape comprising a flexible polyester backing having a thickness of from about 5 to about 15 micrometers, and coated on one surface of the backing is an adhesive layer, wherein the tape has a flexibility measurement of about 1.8 grams, and the flap is capable of remaining in the unfolded position on an overhead projector stage with minimal adhesive transfer at the operating temperature of the overhead projector.

What is claimed is: 
     
       1. An improved envelope for transparencies for overhead projectors, said envelope comprising a) a substantially rectangular pocket of transparent sheet material, said pocket having two longitudinal side edges connected by shorter side edges, said pocket being open at least along one side edge for insertion of a transparency;   b) at least one flap attached in a foldable manner along one of said side edges by means of a flexible adhesive tape, said flap having a folded and an unfolded position, wherein a portion of said flap adjacent to said side edge is opaque, having optical properties selected from the group consisting of light scattering, light blocking and light reflecting properties, such that a majority of light entering said portion of said flap is not transmitted therethrough, and the remaining portion of said flap transmits a majority of light entering said remaining portion of said flap.   
     
     
       2. An improved envelope according to claim 1 wherein said transparent sheet material has a border along at least one edge. 
     
     
       3. An improved envelope according to claim 2 having a border along each edge, thereby framing an image window. 
     
     
       4. An improved envelope according to claim 1 wherein said transparent sheet material is colored. 
     
     
       5. An improved envelope according to claim 1 wherein said transparent sheet material bears a legend thereon. 
     
     
       6. An improved envelope according to claim 1 wherein said portion of said flap transmitting a majority of light entering said portion of said flap is colored. 
     
     
       7. An improved envelope according to claim 1 wherein said opaque portion of said flap adjacent to said side edge is colored. 
     
     
       8. An improved envelope according to claim 1 wherein said pocket has a series of holes therein, adjacent and coextensive with said side edge, wherein said opaque portion of said flap covers said holes in said pocket when said flap is in an unfolded position.